Graphene is an emerging material with potential use in electronics and material sciences. Researchers are always trying to find easier and more efficient ways to create graphene. One method of creating graphene involves reducing graphene oxide to graphene. Graphene oxide is a layered material derived from the oxidation of graphite and is dispersible in water as independent sheets. These sheets may be reduced to graphene by deoxygenating the graphene oxide. As the reduction occurs, it is typical for the graphene sheets to agglomerate with each other, thus crashing as a solid precipitate. A goal is to maintain the uniform dispersibility of these sheets. In other words, agglomeration or clumping in the final product should be minimized as much as possible.
One chemical method of deoxygenating graphene oxide uses hydrazine. Exposing a graphene oxide solution to hydrazine typically causes graphene platelets to precipitate out of the solution. Recent literature reports indicate that careful control of pH and hydrazine concentration can alleviate the tendency of the graphene sheets to agglomerate upon reduction. The requirements of carefully adjusted pH and the removal of hydrazine using dialysis, render this method commercially unattractive. Hydrazine is also a hazardous material that is explosive and highly toxic. The use of hydrazine in this process means that special handling is needed. Also, when using hydrazine, platelets of the graphene tend to agglomerate or clump over prolonged periods. A method of producing graphene without dangerous chemicals would be desirable. A dispersion of individual sheets of graphene that does not contain clumps is more desirable and allows for the use of the resultant product in applications, such as transparent conductors, filler materials for composites or polymeric films.
Thermal deoxygenating is another method of deoxygenating sheets of graphene oxide. This method, however, requires exposing the graphene oxide to temperatures in excess of 1000° C. This process is also slow and requires the use of an inert gas atmosphere, such as Argon. The requirement for an inert gas atmosphere and exceedingly high temperatures makes the creation of graphene more cumbersome. The product of thermal decomposition tends to occur as crumpled sheets instead of flat sheets which also limit the commercial usefulness of the sheets.